--- /dev/null
+/* Asymmetric public-key cryptography key type
+ *
+ * See Documentation/security/asymmetric-keys.txt
+ *
+ * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+#include <keys/asymmetric-subtype.h>
+#include <keys/asymmetric-parser.h>
+#include <linux/seq_file.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/ctype.h>
+#include "asymmetric_keys.h"
+
+MODULE_LICENSE("GPL");
+
+static LIST_HEAD(asymmetric_key_parsers);
+static DECLARE_RWSEM(asymmetric_key_parsers_sem);
+
+/**
+ * asymmetric_key_generate_id: Construct an asymmetric key ID
+ * @val_1: First binary blob
+ * @len_1: Length of first binary blob
+ * @val_2: Second binary blob
+ * @len_2: Length of second binary blob
+ *
+ * Construct an asymmetric key ID from a pair of binary blobs.
+ */
+struct asymmetric_key_id *asymmetric_key_generate_id(const void *val_1,
+ size_t len_1,
+ const void *val_2,
+ size_t len_2)
+{
+ struct asymmetric_key_id *kid;
+
+ kid = kmalloc(sizeof(struct asymmetric_key_id) + len_1 + len_2,
+ GFP_KERNEL);
+ if (!kid)
+ return ERR_PTR(-ENOMEM);
+ kid->len = len_1 + len_2;
+ memcpy(kid->data, val_1, len_1);
+ memcpy(kid->data + len_1, val_2, len_2);
+ return kid;
+}
+EXPORT_SYMBOL_GPL(asymmetric_key_generate_id);
+
+/**
+ * asymmetric_key_id_same - Return true if two asymmetric keys IDs are the same.
+ * @kid_1, @kid_2: The key IDs to compare
+ */
+bool asymmetric_key_id_same(const struct asymmetric_key_id *kid1,
+ const struct asymmetric_key_id *kid2)
+{
+ if (!kid1 || !kid2)
+ return false;
+ if (kid1->len != kid2->len)
+ return false;
+ return memcmp(kid1->data, kid2->data, kid1->len) == 0;
+}
+EXPORT_SYMBOL_GPL(asymmetric_key_id_same);
+
+/**
+ * asymmetric_key_id_partial - Return true if two asymmetric keys IDs
+ * partially match
+ * @kid_1, @kid_2: The key IDs to compare
+ */
+bool asymmetric_key_id_partial(const struct asymmetric_key_id *kid1,
+ const struct asymmetric_key_id *kid2)
+{
+ if (!kid1 || !kid2)
+ return false;
+ if (kid1->len < kid2->len)
+ return false;
+ return memcmp(kid1->data + (kid1->len - kid2->len),
+ kid2->data, kid2->len) == 0;
+}
+EXPORT_SYMBOL_GPL(asymmetric_key_id_partial);
+
+/**
+ * asymmetric_match_key_ids - Search asymmetric key IDs
+ * @kids: The list of key IDs to check
+ * @match_id: The key ID we're looking for
+ * @match: The match function to use
+ */
+static bool asymmetric_match_key_ids(
+ const struct asymmetric_key_ids *kids,
+ const struct asymmetric_key_id *match_id,
+ bool (*match)(const struct asymmetric_key_id *kid1,
+ const struct asymmetric_key_id *kid2))
+{
+ int i;
+
+ if (!kids || !match_id)
+ return false;
+ for (i = 0; i < ARRAY_SIZE(kids->id); i++)
+ if (match(kids->id[i], match_id))
+ return true;
+ return false;
+}
+
+/**
+ * asymmetric_key_hex_to_key_id - Convert a hex string into a key ID.
+ * @id: The ID as a hex string.
+ */
+struct asymmetric_key_id *asymmetric_key_hex_to_key_id(const char *id)
+{
+ struct asymmetric_key_id *match_id;
+ size_t hexlen;
+ int ret;
+
+ if (!*id)
+ return ERR_PTR(-EINVAL);
+ hexlen = strlen(id);
+ if (hexlen & 1)
+ return ERR_PTR(-EINVAL);
+
+ match_id = kmalloc(sizeof(struct asymmetric_key_id) + hexlen / 2,
+ GFP_KERNEL);
+ if (!match_id)
+ return ERR_PTR(-ENOMEM);
+ match_id->len = hexlen / 2;
+ ret = hex2bin(match_id->data, id, hexlen / 2);
+ if (ret < 0) {
+ kfree(match_id);
+ return ERR_PTR(-EINVAL);
+ }
+ return match_id;
+}
+
+/*
+ * Match asymmetric keys by an exact match on an ID.
+ */
+static bool asymmetric_key_cmp(const struct key *key,
+ const struct key_match_data *match_data)
+{
+ const struct asymmetric_key_ids *kids = asymmetric_key_ids(key);
+ const struct asymmetric_key_id *match_id = match_data->preparsed;
+
+ return asymmetric_match_key_ids(kids, match_id,
+ asymmetric_key_id_same);
+}
+
+/*
+ * Match asymmetric keys by a partial match on an IDs.
+ */
+static bool asymmetric_key_cmp_partial(const struct key *key,
+ const struct key_match_data *match_data)
+{
+ const struct asymmetric_key_ids *kids = asymmetric_key_ids(key);
+ const struct asymmetric_key_id *match_id = match_data->preparsed;
+
+ return asymmetric_match_key_ids(kids, match_id,
+ asymmetric_key_id_partial);
+}
+
+/*
+ * Preparse the match criterion. If we don't set lookup_type and cmp,
+ * the default will be an exact match on the key description.
+ *
+ * There are some specifiers for matching key IDs rather than by the key
+ * description:
+ *
+ * "id:<id>" - find a key by partial match on any available ID
+ * "ex:<id>" - find a key by exact match on any available ID
+ *
+ * These have to be searched by iteration rather than by direct lookup because
+ * the key is hashed according to its description.
+ */
+static int asymmetric_key_match_preparse(struct key_match_data *match_data)
+{
+ struct asymmetric_key_id *match_id;
+ const char *spec = match_data->raw_data;
+ const char *id;
+ bool (*cmp)(const struct key *, const struct key_match_data *) =
+ asymmetric_key_cmp;
+
+ if (!spec || !*spec)
+ return -EINVAL;
+ if (spec[0] == 'i' &&
+ spec[1] == 'd' &&
+ spec[2] == ':') {
+ id = spec + 3;
+ cmp = asymmetric_key_cmp_partial;
+ } else if (spec[0] == 'e' &&
+ spec[1] == 'x' &&
+ spec[2] == ':') {
+ id = spec + 3;
+ } else {
+ goto default_match;
+ }
+
+ match_id = asymmetric_key_hex_to_key_id(id);
+ if (IS_ERR(match_id))
+ return PTR_ERR(match_id);
+
+ match_data->preparsed = match_id;
+ match_data->cmp = cmp;
+ match_data->lookup_type = KEYRING_SEARCH_LOOKUP_ITERATE;
+ return 0;
+
+default_match:
+ return 0;
+}
+
+/*
+ * Free the preparsed the match criterion.
+ */
+static void asymmetric_key_match_free(struct key_match_data *match_data)
+{
+ kfree(match_data->preparsed);
+}
+
+/*
+ * Describe the asymmetric key
+ */
+static void asymmetric_key_describe(const struct key *key, struct seq_file *m)
+{
+ const struct asymmetric_key_subtype *subtype = asymmetric_key_subtype(key);
+ const struct asymmetric_key_ids *kids = asymmetric_key_ids(key);
+ const struct asymmetric_key_id *kid;
+ const unsigned char *p;
+ int n;
+
+ seq_puts(m, key->description);
+
+ if (subtype) {
+ seq_puts(m, ": ");
+ subtype->describe(key, m);
+
+ if (kids && kids->id[1]) {
+ kid = kids->id[1];
+ seq_putc(m, ' ');
+ n = kid->len;
+ p = kid->data;
+ if (n > 4) {
+ p += n - 4;
+ n = 4;
+ }
+ seq_printf(m, "%*phN", n, p);
+ }
+
+ seq_puts(m, " [");
+ /* put something here to indicate the key's capabilities */
+ seq_putc(m, ']');
+ }
+}
+
+/*
+ * Preparse a asymmetric payload to get format the contents appropriately for the
+ * internal payload to cut down on the number of scans of the data performed.
+ *
+ * We also generate a proposed description from the contents of the key that
+ * can be used to name the key if the user doesn't want to provide one.
+ */
+static int asymmetric_key_preparse(struct key_preparsed_payload *prep)
+{
+ struct asymmetric_key_parser *parser;
+ int ret;
+
+ pr_devel("==>%s()\n", __func__);
+
+ if (prep->datalen == 0)
+ return -EINVAL;
+
+ down_read(&asymmetric_key_parsers_sem);
+
+ ret = -EBADMSG;
+ list_for_each_entry(parser, &asymmetric_key_parsers, link) {
+ pr_debug("Trying parser '%s'\n", parser->name);
+
+ ret = parser->parse(prep);
+ if (ret != -EBADMSG) {
+ pr_debug("Parser recognised the format (ret %d)\n",
+ ret);
+ break;
+ }
+ }
+
+ up_read(&asymmetric_key_parsers_sem);
+ pr_devel("<==%s() = %d\n", __func__, ret);
+ return ret;
+}
+
+/*
+ * Clean up the preparse data
+ */
+static void asymmetric_key_free_preparse(struct key_preparsed_payload *prep)
+{
+ struct asymmetric_key_subtype *subtype = prep->type_data[0];
+ struct asymmetric_key_ids *kids = prep->type_data[1];
+ int i;
+
+ pr_devel("==>%s()\n", __func__);
+
+ if (subtype) {
+ subtype->destroy(prep->payload[0]);
+ module_put(subtype->owner);
+ }
+ if (kids) {
+ for (i = 0; i < ARRAY_SIZE(kids->id); i++)
+ kfree(kids->id[i]);
+ kfree(kids);
+ }
+ kfree(prep->description);
+}
+
+/*
+ * dispose of the data dangling from the corpse of a asymmetric key
+ */
+static void asymmetric_key_destroy(struct key *key)
+{
+ struct asymmetric_key_subtype *subtype = asymmetric_key_subtype(key);
+ struct asymmetric_key_ids *kids = key->type_data.p[1];
+
+ if (subtype) {
+ subtype->destroy(key->payload.data);
+ module_put(subtype->owner);
+ key->type_data.p[0] = NULL;
+ }
+
+ if (kids) {
+ kfree(kids->id[0]);
+ kfree(kids->id[1]);
+ kfree(kids);
+ key->type_data.p[1] = NULL;
+ }
+}
+
+struct key_type key_type_asymmetric = {
+ .name = "asymmetric",
+ .preparse = asymmetric_key_preparse,
+ .free_preparse = asymmetric_key_free_preparse,
+ .instantiate = generic_key_instantiate,
+ .match_preparse = asymmetric_key_match_preparse,
+ .match_free = asymmetric_key_match_free,
+ .destroy = asymmetric_key_destroy,
+ .describe = asymmetric_key_describe,
+};
+EXPORT_SYMBOL_GPL(key_type_asymmetric);
+
+/**
+ * register_asymmetric_key_parser - Register a asymmetric key blob parser
+ * @parser: The parser to register
+ */
+int register_asymmetric_key_parser(struct asymmetric_key_parser *parser)
+{
+ struct asymmetric_key_parser *cursor;
+ int ret;
+
+ down_write(&asymmetric_key_parsers_sem);
+
+ list_for_each_entry(cursor, &asymmetric_key_parsers, link) {
+ if (strcmp(cursor->name, parser->name) == 0) {
+ pr_err("Asymmetric key parser '%s' already registered\n",
+ parser->name);
+ ret = -EEXIST;
+ goto out;
+ }
+ }
+
+ list_add_tail(&parser->link, &asymmetric_key_parsers);
+
+ pr_notice("Asymmetric key parser '%s' registered\n", parser->name);
+ ret = 0;
+
+out:
+ up_write(&asymmetric_key_parsers_sem);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(register_asymmetric_key_parser);
+
+/**
+ * unregister_asymmetric_key_parser - Unregister a asymmetric key blob parser
+ * @parser: The parser to unregister
+ */
+void unregister_asymmetric_key_parser(struct asymmetric_key_parser *parser)
+{
+ down_write(&asymmetric_key_parsers_sem);
+ list_del(&parser->link);
+ up_write(&asymmetric_key_parsers_sem);
+
+ pr_notice("Asymmetric key parser '%s' unregistered\n", parser->name);
+}
+EXPORT_SYMBOL_GPL(unregister_asymmetric_key_parser);
+
+/*
+ * Module stuff
+ */
+static int __init asymmetric_key_init(void)
+{
+ return register_key_type(&key_type_asymmetric);
+}
+
+static void __exit asymmetric_key_cleanup(void)
+{
+ unregister_key_type(&key_type_asymmetric);
+}
+
+module_init(asymmetric_key_init);
+module_exit(asymmetric_key_cleanup);
Code Review / kvmfornfv.git / blobdiff